Conventionally, examples of a motor in which the rotation number of a rotor is switchable are disclosed in Japanese Patent Application Laid-Open Publication Nos. JP2007202391, JP2007143278, and JP201093977. The motor described in Japanese Patent Application Laid-Open Publication Nos. JP2007202391 and JP2007143278 has a case, a magnet accommodated in the case, an armature rotatably provided inside the case and having a coil wound therearound, a shaft which rotates integrally with the armature, a commutator provided to the shaft, and a high-speed-operation brush and a low-speed-operation brush each of which is in contact with the commutator. When a driver operates a switch to select low-speed driving, a current flows through the low-speed-operation brush to cause the shaft to rotate at a low rotation number. On the other hand, when the driver operates the switch to select high-speed driving, a current flows through the high-speed-operation brush to cause the shaft to rotate at a high rotation number.
On the other hand, the motor described in Japanese Patent Application Laid-Open Publication No. JP201093977 has an annular-shaped stator fixed to the inner surface of a yoke housing and having a plurality of armature coils wound therearound, a rotor rotatably located inside the stator and having a rotating shaft, and a magnet provided to the rotating shaft. In the motor described in this Japanese Patent Application Laid-Open Publication No. JP201093977, magnetizing currents different in phase from each other are supplied to the plurality of armature coils to generate a revolving magnetic field, thereby causing the rotor to rotate. Additionally, the motor described in Japanese Patent Application Laid-Open Publication No. JP201093977 does not have brushes which are described in Japanese Patent Application Laid-Open Publication Nos. JP2007202391 and JP2007143278.